Beneficial agents such as for example skin care or fabric care agents or perfume can be incorporated in liquid form into washing, cleaning or treatment agents, normally by spraying, or in solid form by blending the beneficial agent with the washing, cleaning or treatment agent or also with a component of the respective agent. Several disadvantages result from this procedure: The beneficial agent that makes up only a minor fraction of the ready-made washing, cleaning or treatment agent cannot be homogeneously blended with the other components of the washing, cleaning or treatment agent, such that the ready-made agent exhibits differing properties that depend on the amount of beneficial agent that is comprised in each considered batch (e.g. in the separate amount dosed by the consumer). If the beneficial agent is volatile, unstable to light or air or it reacts with the other components comprised in the washing, cleaning or treatment agent, then only a reduced amount of the beneficial agent remains available for the advantageous administration at the desired time. Furthermore, the decomposition products and reaction products of the beneficial agent or of the co-reactants can impair the performance of the washing, cleaning or treatment agent. If for example perfume is sprayed onto a washing, cleaning or treatment agent in a post addition step, then individual components of this perfume already volatilize as of this point in time; furthermore the danger exists that the perfume will decompose over time, for example due to the interaction with likewise comprised bleach compounds or surfactants. The perfume lends a pleasant smell to the washing, cleaning or treatment agent, as well as to the wash liquid, into which it is transferred during the washing, cleaning or treatment process, and in many cases for a short time even to the surfaces treated with the wash liquid. However, a longer term fragrance effect is not achieved, because the perfume fractions that actually remain on the treated surfaces after drying evaporate away.
The above disadvantages can be overcome by encapsulating one or more of the beneficial agents. However, the incorporation of encapsulated beneficial agents that in the manufacture of the capsules mostly involve a liquid liquid-capsule mixture—abb. capsule slurry—is very problematic for the person skilled in the art in washing, cleaning or treatment agents.
If the capsule slurry is sprayed on, then the problem arises that the frequently fragile capsules are unable to withstand the mechanical forces that occur during spraying, and consequently a considerable amount of capsule breakage and release of beneficial agent occur during the spraying process. The released beneficial agent can once more be destroyed or evaporate without hindrance and thereby is no longer available for advantageous administration at the intended time.
If, on the other hand, the capsule slurry is “heaped up” on the particulate material and, bearing in mind the fragility of the capsules, is blended in with low, or at most, average shear, then clumps are formed due to agglomeration, which also limits the free-flowability of the ready-made agent. At the microscopic level, capsule agglomerates are also formed which are combined with the carrier material (carrier agglomerates). Systems of this kind are characterized by the particularly poor resistance against mechanical forces, thereby again resulting in poor storage stability and transportability. The breakage of the capsules that are located on exposed positions on the carrier material also causes a premature release of the beneficial agent, which evaporates and/or reacts with light, air or other components thereby leading to discoloration, loss of performance and deterioration of the fragrance of the agent. If a capsule slurry is heaped onto particulate material, the liquid of the capsule slurry moreover partially dissolves or even dissolves the water-soluble components of the particulate materials, thereby destroying the powder structure of the washing, cleaning or treatment agent and leads to a clear deterioration of the appearance of the agent, to a reduction of its effectiveness as well as to a significant change in the bulk properties of the particulate product (bulk density, particle size distribution, flow properties). Even when the capsule slurry is “heaped on” or “run in”, a homogeneous dispersion of the encapsulated beneficial agent in the finished made up washing, cleaning or treatment agent cannot be achieved.
If, prior to blending with the usual components of the washing, cleaning or treatment agent, the capsule slurry is dried, then in addition to the problem of the mechanical forces on the capsule there is also the problem of the exposure to heat, such that this processing possibility seems not to be suitable, especially for fragile capsules, as well as for capsules, whose shells and/or cores is/are unstable to heat.
Therefore there is a need to overcome some—preferably all—of the abovementioned disadvantages.